I use these role cards whenever I put my students into groups. These are very helpful with getting all students to do their work and making sure that each group member is "busy" and not just sitting and waiting on one person to do all of the work.
Jobs for students. I use this so my students will not all yell out to volunteer to do certain things and as a way to make sure the simple things get done. It really helps. I use this in my 5th grade classroom.